I'm not sure if these have been requested to be acted upon properly in the past or not, but I'm pretty sure somebody should have complained at some point in the past.

Notably, \r and \b are ignored.
\r should simply return to the beginning of the line.
\b should do a backspace, without a rubout.
These two are fairly important to make progress displays. I'm not asking for full cursor controls, but these two would be very helpful to have and shouldn't be a huge leap to implement, considering \t does work.